Selective bore wellhead lubricator system



June 30, 1970 W. H. PETERSEN 3, 1

SELECTIVE BORE WELLHEAD LUBRICATOR SYSTEM Filed Jan. 8, 1969 3 Sheets-Sheet 1 F I G.

INVENTOR WILLIAM H1. PETERSEN BY! HIS ATT CVEY 2 June 30, 1970 w. H. PETERSEN SELECTIVE BORE WELLHEAD LUBRICATOH SYSTEM 3 Sheis-Sheet 2 Filed Jan. 8, 1969 FIG. 2

INVENTORI June 30, 1970" w. H. PETERSEN 3,517,738

SELECTIVE BORE WELLHEAD LUBRICATOR SYSTEM v 3 Shegts-5het 3 Filed Jan. 8, 1969 FIG. 4

FIG. 3

'INVENTORZ WILLIAM H. PETERSEN HIS ATTORNEY FIG. 5

United States Patent Oflice 3,517,738 Patented June 30, 1970 U.S. Cl. 166.6 Claims ABSTRACT OF THE DISCLOSURE A lubricator mechanism for use with underwater wells and including indexing means for placing a single tube production riser into selective engagement with each of a plurality of tubing runs in a well in a sequential This invention relates to offshore well operations and pertains more particularly to apparatus for selectively establishing operative communication between a singletube production riser and each of a number of tubing strings associated with an underwater well for the purpose of carrying out installation, maintenance, or other operations with respect thereto.

In an attempt to locate new oil fields, an increasing amount of well drilling has been conducted at offshore locations, such, for example, as off the coast of California, Louisiana and Texas. As a general rule, the strings of casings in a well, together with the tubing string or strings, extend to a point above the surface of the water where they are closed in a conventional manner that is used on land wells, with a conventional wellhead assembly being attached to the top of the casing. Recently, methods and apparatus have been developed for drilling and completing wells wherein both the 'well casinghead, and subsequently the wellhead assembly and casing closure device, are located under water at a depth suflicient to allow ships to pass over them. Preferably, the casinghead and the wellhead closure assemblies are located close to the ocean floor.

It is, of course, necessary to periodically perform workover or maintenance operations with respect to an underwater well. For this purpose, communication, as by means of a marine conductor pipe or production riser, may be established between a floating workover vessel and the underwater well so that the desired operations may be carried out therebetween. Underwater wells may have associated therewith more than one tubing string, which strings may extend, for example, to different production Zones. In the course of carrying out operations of the above-described type, it is often desirable to have full-bore access to each of the multiple tubing strings. One prior art approach for accomplishing this end has been to provide the production riser with a number of tubular elements correspondingto the number of tubing strings associated with the well. The tubular ele ments are placed into communication with the respective tubing strings so that operations, such as the lowering of special plugs or valves into the tubing strings, may be carried out through each of the tubular elements.

The incorporation of a number of tubular elements in a production riser system, of course, greatly adds to the cost thereof, a factor that becomes increasingly important as deeper waters are encountered during operations.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide apparatus which will permit full bore operations to be carried out with respect to multiple tubing strings associated with an underwater well through a single tube production riser.

This and other objects have been attained in the present invention by providing a wellhead lubricator mechanism operatively associated with a single tube production riser and a multiple tubing string underwater well, said lubricator mechanism including indexing means whereby the riser tube may be selectively placed into operative engagement with each of said tubing strings. Thisindexing may be accomplished remotely, as by means of an electric or hydraulic motor, with the lubricator attached to the underwater well head or wellhead assembly.

DESCRIPTION OF THE DRAWING Other objects, purposes and characteristic features of the present invention will be obvious from the accompanying drawing and from the following description of the invention. In describing the invention in detail, reference will be made to the accompanying drawing in which like reference characters designate corresponding parts throughout several views and in which:

'FIG. 1 is a diagrammatic view illustrating a barge or vessel floating on the surface of a body of water over an underwater wellhead assembly, the vessel having depending therefrom the lubricator mechanism according to the present invention;

FIG. 2 is a longitudinal view illustrating the lubricator mechanism according to the present invention in operative engagement with an underwater wellhead assembly;

FIGS. 3 and 4 are longitudinal, partial cross-sectional views illustrating the lubricator mechanism according to the present invention attached to the underwater wellhead assembly at different stages in the operation of said lubricator mechanism; and

FIG. 5 is a plan view in partial cross-section showing details of an alternative form of motor which may comprise a portion of the lubricator mechanism according to the present invention.

Referring to FIG. 1 of the drawing, a workover vessel or barge 11 of any suitable floatable type is illustrated as floating on the surface of a body of water 12 and substantially fixedly positioned over a preselected location by suitable barge positioning means or by being anchored to the ocean floor 13 by suitable anchors (not shown) connected to anchor lines 14 and 15. Equipment of this type may be used in carrying out operations in water depths varying from about to 1500 feet or more. Barge 11 is equipped with a suitable der-rick 16 as well as other conventional auxiliary equipment needed during well workover, maintenance or other similar operations. The derrick 16 is positioned over a slot 17 which extends vertically through the barge in a conventional manner. When using the equipment according to the present invention, the slot 17 of vessel 11 may be either centrally located or extend in fom one edge of the barge. However, operations may be carried out over the side of the barge or vessel without the use of a slot.

An underwater wellhead structure is illustrated in FIG. 1 as comprising a base member 18 which is positioned on the ocean floor 13 and is fixedly secured to a large diameter well casing 19 which extends down into a well, which has been previously drilled, and is preferably cemented therein. Two strings of production tubing 20* and 21 are suspended within the well casing and extend into the well in the usual manner. If desired, the wellhead structure may include two or more vertical guide columns 22 and 23 having secured thereto guide lines 24 and 25. Guide lines 24 and 25 extend upwardly to vessel 11 and are secured thereto in any known manner such, for example, as being secured to constant tension hoists on board the vessel.

Positioned on base member 18 is a casinghead unit 26 with a wellhead assembly or production control unit 27 attached thereto. Normally, the production control unit or wellhead assembly is in fluid communication with the production tubing and comprises the necessary piping,

valves, chokes, and other equipment normally connected togther and mounted on the top of a well, and known as a Christmas tree, together with the necessary hydraulic .or electrical systems, including pumps, reservoirs, motors, etc., to operate the valves at the head of the well from a remote location. A typical example of a suitable underwater production control unit or Wellhead assembly for use at an oifshore well location, and its manner of operation, is shown and described in US. Pat. No. 3,064,735, issued Nov. 20, 1962, to R. J. Bauer et al. For purposes of illustration, it will be assumed that the wellhead assembly utilized in conjunction with the present invention will be similar to that described in the above patent, although it is, of course, obvious that the lubricator assembly or mechanism according to the present invention could be used with other suitable Wellhead assembly designs. For that matter, the'apparatus according to the present invention may be placed in direct operative relationship with the underwater wellhead itself in the absence of the wellhead assembly which may have been removed previously or prior to its installation on the ocean floor.

Wellhead assembly 27 includes two fluid flow handling conduits (only one of which, i.e. conduit 28, is shown) and an upstanding Wellhead entry conduit or mandrel 29. Fluid flow handling conduit 28 communicates with one of production tubing strings and 21 while the other of said fluid flow handling conduits (not shown) is in communication with the other of said production tubing strings. Fluid flow handling conduit 28 is in communication through flow line connector 30 with flow line 31 which extends to a production fluid collecting facility (not shown) either on shore or disposed offshore as desired. The other fluid flow handling conduit (not shown) which is associated with the wellhead assembly is in fluid-flow communication with another flow line (not shown). In other words, it is to be understood that one fluid flow handling conduit and one flow line combination are to be provided for each tubing string associated with the well with which the lubricator mechanism according to the present invention is brought into engagement.

The lubricator mechanism or assembly according to the present invention is indicated generally by means of reference numeral 35 and is shown in FIG. 1 as being lowered from vessel 11 along guide lines 24 and by means of a single tube production riser 33 which extends upwardly to the vessel and is secured thereto in any known manner. Preferably, the production riser 33 will depend from the vessel through the intermediary of a compensation mechanism (not shown) which serves to maintain the lower end of the riser at a substantially fixed position relative to the underwater wellhead assembly. Compensation devices of this type are well known in the art and may take the form of hydraulic or counterweight mechanisms, for example. The operation of lowering the lubricator assembly or mechanism 35 is, of course, carried out by extending the length of production riser 33 through the addition of individual riser sections thereto in the customary manner.

As may be seen most clearly with reference to FIGS. 2-4, 1ubricator assembly 35 includes a primary connector element which is adapted to secure the lubricator assembly to the wellhead assembly after the lubricator assembly has been lowered into position on the wellhead assembly in the manner previously described, i.e. through the lengthening of the production riser 33 on board vessel 11. The primary connector element includes an upstanding sleeve member 36 which flares outwardly at the bottom thereof to provide a skirt element 37. Extending from sleeve member 36 and skirt element 37 is an open framework 38 upon which are mounted guide tubes 39 and 40 which surround guide lines 24 and 25 and are freely slidable with respect thereto. The guide lines and guide tubes cooperate to position the lubricator assembly 35 over the wellhead assembly 27 during the abovedescribed lowering operation in an obvious manner. The skirt element 37 addition ally ensures proper placement of the lubricator assembly over the wellhead assembly by cooperating with upstanding mandrel 29 of the wellhead assembly in an obvious manner so that the mandrel enters into sleeve member 36 as the wellhead assembly and lubricator assembly are brought into engagement.

With particular reference to FIGS. 3 and 4, it may be seen that sleeve member 36 terminates at the upper end thereof in an integral cross plate 41. Aflixed to the inner wall of sleeve member 36 is an integral inner projecting key element 42. Key element 42 cooperates with a groove 43 formed along one side of upstanding mandrel 29 of the wellhead assembly. Groove 43 is preferably V-shaped as shown most clearly in FIG. 1 and it is to be understood that downward movement of lubricator assembly 35 over mandrel 29 will effect rotational alignment between the wellhead assembly and the lubricator assembly due to the cooperative relationship between key element 42 and groove 43. Downward movement of the lubricator as sembly 35 terminates when the crossplate 41 comes into contact with the top of upstanding mandrel 29 as shown in FIGS. 3 and 4. After this contact has been made, latch members 45 and 46, which are mounted in suitable housing aflixed to sleeve member 36, are positioned in recesses 47 and 48 formed in the outer peripheral wall of mandrel 29. Latch members 45 and 46 are locked into position by means of bearing blocks 50 and 51 which are moved to the position illustrated in FIGS. 3 and 4 by means of arms 50a and 51a operatively associated with hydraulic or electrical actuation members 52 and 53 which are mounted upon sleeve member 36 in any desired manner. Actuator members 52 and 53 derive their power from hydraulic or electrical control bundle or hose 55 which is attached to production riser 33 and extends upwardly therealong to vessel 11. In this manner the various constituent lines of the control bundle or hose may be energized on board the vessel to carry out the desired operations. It should be noted at this juncture that the primary connector component may incorporate hydraulic or electrical stabs or connectors such as stabs 56 and 57 which are illustrated as extending downwardly from crossplate 41. These stabs or connectors are associated with one or more of the lines of the control bundle and are adapted to enter into cooperating recesses in the upstanding mandrel 29 as shown in FIGS. 3 and 4 when the lubricator assembly 35 is positioned on the wellhead assembly. Although for purposes of simplicity such have not been illustrated, it should be assumed that the recesses of mandrel 29 which accom modate stabs 56 and 57 communicate with suitable control lines, valves, locks, etc., associated with the well and/or the wellhead assembly. In this manner, certain operations may be carried out with respect to the wellhead assembly or well itself directly through the control hose or bundle.

Operatively associated with the primary connector component and also comprising part of the lubricator assembly 35 is a tubular-shaped indexing spool member 60 which is connected to single tube production riser 33 by any suitable coupling or connector means. Communication is provided through the indexing spool member 60, as by means of a pipe segment 61 between the production riser and a stab-type coupler pipe 62 which extends downwardly and outwardly from the main body of the indexing spool member 60 in the manner shown in FIGS. 3 and 4. Also attached to spool member 60 is a high pressure hose 63 which extends upwardly along production riser 33 (and being attached thereto by any desired expedient) to vessel 11. The flexible high pressure hose provides a pressuretight flow conduit (not full bore) between the surface vessel and the tubing run or runs not connected to the steel pipe rised. Flow access is often required into the other runs when installing or retrieving plugs or valves through the steel pipe riser. This conduit can effectively be provided by use of an easily-handled hose. Communication between the high pressure hose and a second coupler pipe 64 is provided through the indexing spool member 60 by means of a second pipe segment (not shown) similar in construction to pipe 61.

Spool member 60 is mounted for rotatable movement within a throughbore 65 defined by a drive housing 66 which defines an annular inwardly-facing channel, 67 said channel being in communication with throughbore 65 and having disposed therein thrust bearings (68 and 69) to allow easy rotation of index spool 60. A large slave gear 70 is fixedly positioned about the periphery of spool member 60 in the manner shown and the slave is restrained against axial or up-and-down movement by said bearings while at the same time being capable of slidable rotating movement with respect thereto. A drive gear 71 is disposed in channel 67 as shown and is in engagement with slave gear 70. Drive gear 71 is mounted on a shaft 72 which comprises a part of hydraulic or electric drive motor 73 which is actuated by means of one or more of the control lines of the control bundle or hose 55. Extending downwardly from drive housing 66 and integrally connected thereto are a pair of spaced arms 74 and 75 which extend through apertures 76 and 77 formed in crossplate 41 and are integrally connected at their lowermost ends to a flange member 78 which extends around upstanding sleeve member 36 of the primary connector element and is slidable in an up-and-down manner with respect thereto. 'Ihreadedly engaged to flange member 78 and extending upwardly therefrom are a pair of drive rods 81 and 82 which are operatively associated with piston members (not shown) disposed within hydraulic cylinder members 83 and 84 which are mounted upon crossplate 41 in any known manner-the drive rods extending through suitable apertures formed in the crossplate 41 as shown. By pressuring up the piston members (not shown) within cylinder members 83 and 84 on either one or the other side thereof in an obvious manner the drive rods 81 and 82 will either extend outwardly of the cylinders as shown in FIG. 3 or will retract therein as shown in FIG. 4. When the drive rods are in the former position, i.e. the extended position, coupler pipes 62 and 64 are stabbed into recesses 85 and 86 which are formed in upstanding mandrel 29, thus placing the coupler pipes into communication with the strings of production tubing and 21, which extend upwardly into the mandrel as shown and are secured thereto by any known expedient, e.g. thread connectors. It is to be appreciated that by reversing the side of the piston members upon which hydraulic pressure is applied, the drive rods 81 and 82 are brought to the retracted position illustrated in FIG. 4. With particular reference to this latter figure, it may be seen that by retracting the drive rods 81 and 82, flange member 78 and hence spool member 60 are pulled upwardly with respect to both mandrel 29 and the primary connector element of lubricator assembly 35. Since single tube production riser 33, as Well as control bundle 55 and high pressure hose 63, are preferably operatively associated with suitable conventional counterweight or tensioning equipment (not shown) on board vessel 11, these latter-mentioned components will also freely move in an upwardly direction during upward movement of spool member 60.

The operation of the apparatus according to the present invention will now be described. As previously stated, lubricator assembly 35 is initially lowered into engagement with wellhead assembly 27 by gradually lengthening production riser 33 through the addition of individual riser sections with guide lines 24 and ensuring that skirt element 37 of the lubricator assembly extends over upstanding mandrel 29 as the lubricator assembly and the wellhead assembly are brought into engagement. As the lubricator assembly is still further lowered the above-described key element 42 and groove 43 cooperate to effect rotational alignment between the lubricator assembly and the wellhead assembly. Downward movement of lubricator assembly terminates when crossplate 41 contacts the top of mandrel 29 and latch members and 46 are locked into position in recesses 47 and 48 which are formed in the outer peripheral wall of mandrel 29 to secure the lubricator assembly to the wellhead assembly.

Assuming that drive rods 81 and 82 are in their extended position during at least the final stages of the above-described lowering operation, coupler pipes 62 and 64 are stabbed into recesses and 86 in the same manner shown in FIG. 3 as the lubricator assembly is brought into final engagement with the wellhead assembly. At this stage full-bore access may be had through single tubing production riser 33 to production tubing string 20. Such full-bore access may be required to lower special plugs, valves, etc., into the well during installation, maintenance or other operations. High pressure hose -63-, on the other hand, may be utilized to carry out operations not requiring full-bore access with respect to production tubing string 21 through coupler pipe 64. Safety lock mechanisms such as latch devices 90 and 91 are preferably employed to ensure that spool member 60 is held down during the operations through the tubing strings even though hydraulic power to hydraulic cylinder members 83 and 84 may be lost for some reason. Latch devices 90 and 91, in other words, would incorporate suitable conventional fail-safe mechanisms to ensure the positioning of latch heads 92 and 93 thereof into recesses formed on the outer peripheral surface of sleeve member 36 of the lubricator assembly primary connector element even upon failure of hydraulic power to the lubricator assembly system.

After the desired full-bore operations have been carried out with respect to production tubing string 20, it may be desired to carry out similar operations with respect to tubing string 21. If so, latch heads 92 and 93 are withdrawn from the cooperating recesses of sleeve member 36 and hydraulic fluid is introduced into cylinder members 83 and 84 to bring drive rods 81 and 82 to their respective retracted positions illustrated in FIG. 4. By so doing, spool member 60 is drawn upwardly, thereby removing coupler pipes 62 and 64 from the recesses 85 and 86 formed in upstanding mandrel 29. As previously stated, such action also causes production riser 33, control bundle 55 and high pressure hose 63 to move in an upwardly direction.

After upward movement of spool member 60 has terminated, hydraulic or electric drive motor 73 is actuated, thus causing drive gear 71 to turn. The movement of drive gear 71 is transmitted to slave gear 70, resulting in the rotational movement of spool member 60. It will be appreciated that after the spool member 60 has turned degrees, rotation of the drive motor 73 is terminated and the various elements associated with the apparatus accofding to the present invention will have assumed the respective positions illustrated in FIG. 4. That is, coupler pipe 62, which is associated with single tubing production riser 33, is disposed over recess 86 and tubing string 21, and coupler pipe 64 (operatively associated with high pressure hose 63) is positioned over recess -85 and tubing string 20. Upon movement of drive rods 81 and 82 to the respective extended positions thereof, production riser 33 is placed in full-bore communication with tubing string 21, since coupler pipe 62 is stabbed into recess 86 in a fluid-tight manner. Coupler pipe 64, of course, is stabbed into recess 85 so that any desired operations may be carried out with respect to tubing string 20 through high pressure hose 63.

It is, of course, to be understood that a wide variety of arrangements or expedients may be utilized to eflect the teachings of the present invention. For example, rather than employ the particular form of spool member drive motor that is disclosed, other means for rotating the spool member may be employed. For example, FIG. 5 illustrates one alternative form of spool member rotating means which may be utilized. In this alternative embodiment, the spool member 60 has fixedly positioned about the periphery thereof an outwardly extending flange 101 having a plurality of ratchet teeth 102 formed thereon. An actuator housing 103 is positioned adjacent the spool member with a portion of the flange 101 passing into a slot 104 formed in the actuator housing in the manner illustrated. An actuator block 105 is positioned in housing 103 and has extending therefrom armatures 106 and 107 which pass through apertures formed in housing walls 108 and 109 in a fluid-tight manner to enter into cylinders 111 and 112 respectively. Attached to armatures 106 and 107 and maintained in fluid-tight engagement with the inner walls of cylinders 111 and 112 are piston elements 113 and 114. In communication with the interior of cylinders 111 and 112 are hydraulic lines 115 and 116. By alternatively introducing hydrallic fluid through these lines it will be obvious that pistons 113 and 114, and hence actuation block 105, will move in a reciprocating manner. In so doing, protrusion 115 formed on actuator block 105 will contact in a sequential manner the ratchet teeth 102 formed on flange 101, thereby rotating the spool member 60 to a desired extent. In addition to using alternative forms of spool member rotating means, stop means may be provided on the spool means or other elements of the lubricator assembly associated therewith to ensure that precisely 180 degrees are encompassed during the spool member movement. Such feature, however, is not necessary to proper performance of the apparatus according to the present invention and the incorporation of such an expedient would be obvious to one skilled in the art. Finally, rather than employ an arrangement on the lubricator assembly itself to effect rotation of the spool member it would be possible to effect proper indexing of the spool member and the single tubing production riser merely by manipulating, i.e., rotating, the production riser on board vessel 11.

I claim as my invention:

1. Apparatus lowerable to an underwater wellhead assembly by means of a single tubing riser extending from a vessel floating on the surface of a body of water, said underwater Wellhead assembly having operatively associated therewith a plurality of production tubing strings, said apparatus comprising:

connector means including latch means adapted to secure said apparatus to said wellhead assembly; throughbore defining means defining a throughbore in communication with the interior of said single tubing riser, said throughbore defining means being relatively moveable with respect to said connector means; and

prime mover means operatively associated with said connector means and said throughbore defining means whereby relative movement is effected between said connector means and said throughbore defining means to provide selective full-bore communication between said single tubing riser and each of said plurality of production tubing strings, through said throughbore, in a sequential manner.

2. The apparatus according to claim 1 wherein said throughboredefining means includes a spool member mounted for both axial and rotatable movement with respect to said connector means, said spool means having associated therewith conduit means having the interior thereof in communication with the interior of said single tubing production riser, said conduit means being adapted to be selectively placed in communication with each of said plurailty of tubing strings upon rotatable and axial movement of said spool member.

3. The apparatus according to claim 2 wherein said prime mover means includes gear means fixedly mounted with respect to said spool means, said gear means being operatively associated with motor means whereby rotatable movement of said spool means may be effected.

4. The apparatus according to claim 3 wherein said prime mover means further includes hydraulically actuated drive rod means mounted for reciprocal movement with respect to said connector means and adapted to axially move said spool member with respect to said connector means upon said reciprocal movement.

5. The apparatus according to claim 1 wherein said connector means includes orienting means for ensuring the proper positioning of said apparatus with respect to said Wellhead assembly as said apparatus and said assembly are brought into engagement.

References Cited UNITED STATES PATENTS 3,332,484 7/1967 Watkins .166.6 3,396,789 8/1968 Dean 166-.5

ERNEST R. PURSER, Primary Examiner 

